To assess the clinicopathologic features of small renal masses (≤4 cm) associated with distant metastatic disease.
We identified radical or partial nephrectomies with renal cell carcinomas (RCCs) measuring 4 cm or less in size (pT1a or pT3a) from 2005 to 2015. Clinicopathologic features were compiled.
A total of 590 RCCs 4 cm or less were identified, of which 3.9% were associated with distant metastatic RCC. Metastasis was more common in pT3a tumors 4 cm or less than pT1a tumors (19% vs 2.7%; P < .01). Seventy percent of tumors were clear cell RCCs. Overall, 43% of patients had previously (30%) or subsequently (13%) diagnosed RCC prior to development of metastasis, 80% of which were the same histologic subtype as the small renal mass.
Distant metastatic disease was rarely encountered in patients with small renal masses. Many of the patients with distant metastases had previously or subsequently diagnosed RCC, which could represent the true source of metastatic disease.